INVESTIGATION OF THE RELATIVE CONTRIBUTIONS OF CIGARETTE-SMOKING AND MINERAL DUST EXPOSURE TO ACTIVATION OF CIRCULATING PHAGOCYTES, ALTERATIONS IN PLASMA-CONCENTRATIONS OF VITAMIN-C, VITAMIN-E, AND BETA-CAROTENE, AND PULMONARY DYSFUNCTION IN SOUTH-AFRICAN GOLD MINERS

Objectives-To determine the relative effects of cigarette smoking and mineral dust exposure on numbers and activity of circulating phagocyte s, plasma nutritional antioxidant state, and pulmonary function in Sou th African gold miners. Methods-Pulmonary function was assessed spirom etrically, whereas reactive oxidant generation by circulating phagocyt es, and plasma concentrations of the nutritional antioxidative nutrien ts vitamin C and vitamin E and beta carotene were measured with chemil uminescence, spectrophotometry, or high performance liquid chromatogra phy respectively. Results-Cigarette smoking, but not mineral dust expo sure, was associated with increased numbers and pro-oxidative activity of circulating neutrophils and monocytes, decreased plasma concentrat ions of vitamin C, and pulmonary dysfunction. Discussion-In this study group occupational exposure to mineral dust has not been found to pro mote increases in the numbers or reactivity of circulating phagocytes or to be a significant cause of pulmonary dysfunction, the changes fou nd being due primarily to cigarette smoking.